1. Field of the Invention
The present invention relates to a tire inspection device quite suitable for checking the tire internal pressure and detecting the temperature in the tire, the strain of the tire wheel and the like.
2. Description of the Prior Art
Conventional means for detecting, for example, tire internal pressure (air pressure), are devices including a detection device fitted on the tire side and having detectors which utilize electromagnetic induction, electromagnetic resonance etc. to detect the tire internal pressure even while the automobile is running. They are so-called the non-contact systems. Other devices are also known which transmit the tire internal pressure through a slip ring, ejection rod or the like. They are so-called contact systems. The tire internal pressure detectors of the non-contact systems are complicated, and so have high manufacturing costs. Further, wheels especially made for this system, the modification, etc. of automobiles are required as well. Furthermore, the maintenance of their reliability and environmental durability is difficult. And, what is more, a cost increase is required to solve these problems.
In addition, display-type tire internal pressure detectors have hitherto been developed as a low-cost means. However, when they break down, the tire internal pressure is released to the air due to their original construction. Defective operation is apt to occur under the low temperature during the winter season due to freezing. Therefore, they have problems in reliability and safety, so they have not yet attained a stage of the practical use.
Moreover, with respect to any known tire internal pressure detectors, tire valves are merely manufactured for the purpose of filling the tire with air and maintaining the airtightness, and do not have structure for serving the function of detecting the pressure and temperature in the tire.
As described above, various tire pressure internal detections have been developed. However, no contrivance has been made to the tire valves employed for them. Above all, no fully satisfactory tire pressure detectors have been developed yet to date.